Excitonic Conversions in Semiconductors

Westudied the influence of parametersthatgovern the excitonic conversion phenomena in semiconductors. In thisstudywedefined a surface conversion velocity of excitons to free electron-hole pairs bs and a parameter of exciton dissociation in the space charge layer b (x) related to the electricfield E(x). The influence of bs on the electrons and excitons densities and on the short-circuit current shows thatthisparameteris a generationterm for electrons and a recombinationterm for excitons. In the organicsemiconductorwhere the excitons have a very short lifetime and a binding energysuperior to thermal energy, an exciton conversion model is essential to increase the performance of thesesolarcells. Our studyshowedthat the shortcircuit current has a high value when the exciton conversion speed is of the order of 104 cm.s -1 .